The following description is provided to assist the understanding of the reader. None of the information provided or references cited is admitted to be prior art to the present technology.
The Earth's oceans serve as highways for transporting goods, for the passage of recreational shipping vessels, and for the transport of troops and ammunition necessary for national defense purposes. Ships used for such transport are constantly exposed to harsh, corrosive conditions due to the salinity of sea water and are also exposed to rot and deterioration from biological life forms present in the oceans.
The economic loss to the shipping industry due to corrosion and deterioration of ships sailing the oceans is large. To reduce the economic impact, shipping vessels are protected through the use of antifouling coatings that serve three basic functions. First, the coatings protect the vessel hulls from the corrosive effects of salt water. Second, the coatings can also serve as a decorative and/or color film that permits ease of identification of an ocean liner. Finally, the coatings prevent aquatic life, i.e. biofilms and barnacles, from growing on the hull, which unabated cause drag on the ship and increased fuel consumption. For example, biofilms may increase the drag by 20%, and the growth of barnacles may increase drag by over 60%, when compared to a pristine ship without biological growth. Without removal of the growth of the films or other life forms, such increases in drag can only be overcome by higher fuel consumption for the ships.
While commercially available coatings attempt to address the problem of preventing or minimizing the growth of biofilm and aquatic lifeforms on hulls, the coatings tend to contain environmentally unfriendly chemical compounds that leach off into the ocean and upset the delicate balance of life within the oceans. For instance, many of the presently available coatings contain organotin or organocopper compounds that can have a marked negative impact on the environment.